13 2dPromo XPPen Artist 13 2nd Gen Graphic Tablet Monitor with 130% sRGB 9 Shortcut Keys 13.3 Inch Pen Display Support Android Windows Mac di Mall. Promo khusus penggunaOn putting A=0 and B=13, we can get 13. On putting D=0 and B=13 in eqn (2), we can still get 13. Thus, we can say that the value of D cannot be determed from the given data.